植物学

植物学

封面介绍：Cysteine as well as sulfate inhibits primary root elongation in a dosage dependent manner. In this issue，Wang et al.（pp. 186-197）demonstrate that cysteine regulates the expressions of PLT1/2，SCRand SHR genes to maintain the stem cell niche in root meristem.

L-Cysteine inhibits root elongation through auxin/PLETHORA and SCR/SHR pathway in Arabidopsis thaliana

Zhen Wang，Jie-Li Mao，Ying-Jun Zhao，et al.

L-Cysteine plays a prominent role in sulfur metabolism of plants. However，its role in root development is largely unknown. Here，we report that L-cysteine reduces primary root growth in a dosage-dependent manner. Elevating cellular L-cysteine level by exposingArabidopsis thaliana seedlings to high L-cysteine，buthionine sulphoximine，or O-acetylserine leads to altered auxin maximum in root tips，the expression of quiescent center cell marker as well as the decrease of the auxin carriers PIN1，PIN2，PIN3，and PIN7 of primary roots. We also show that high L-cysteine significantly reduces the protein level of two sets of stem cell specific transcription factors PLETHORA1/2 and SCR/SHR. However，L-cysteine does not downregulate the transcript level of PINs，PLTs，or SCR/SHR，suggesting that an uncharacterized post-transcriptional mechanism may regulate the accumulation of PIN，PLT，and SCR/SHR proteins and auxin transport in the root tips. These results suggest that endogenous L-cysteine level acts to maintain root stem cell niche by regulating basal- and auxin-induced expression of PLT1/2 and SCR/SHR. L-Cysteine may serve as a link between sulfate assimilation and auxin in regulating root growth.

Auxin； L-cysteine； PIN； PLETHORA； root stem cell； root system architecture

来源出版物：Journal of Integrative Plant Biology，2014，57（2）： 186-197联系邮箱：Cheng-Bin Xiang，xiangcb@ustc.edu.cn

气体甲醛胁迫对蚕豆保卫细胞中过氧化氢的积累和气孔导度及开度的影响

孙慧群，周升恩，吴怀胜，等

摘要：以蚕豆为材料，考察气体甲醛（HCHO）胁迫对保卫细胞H2O2积累和叶片气孔导度、开度的影响.结果表明：气体HCHO胁迫增加了叶片中H2O2的积累，荧光显微分析发现在较低浓度（0.2～0.4 μmol•L-1）气体HCHO胁迫下，保卫细胞中增加的H2O2主要分布在细胞质中，高浓度（0.8～1.6 μmol•L-1）气体HCHO胁迫不仅增加保卫细胞质中H2O2的积累，而且显著增加叶绿体中H2O2的含量及积累H2O2的叶绿体数量，这说明在高浓度气体HCHO胁迫下蚕豆保卫细胞中增加的H2O2主要来源于叶绿体和细胞质.保卫细胞中H2O2积累的增加显著降低蚕豆的气孔导度和开度，从而导致蚕豆HCHO吸收效率下降.气体HCHO胁迫下叶片中抗氧化酶活性的变化可能是H2O2积累增加的主要原因，气体HCHO胁迫显著增强叶片中CAT和SOD的活性，但只有低浓度HCHO胁迫诱导叶片POD活性，叶片APX对HCHO胁迫很敏感，低浓度的气体HCHO对叶片APX活性都有显著的抑制作用.

关键词：气体甲醛胁迫；蚕豆；保卫细胞；过氧化氢积累；抗氧化酶

来源出版物：植物生理学报，2015，51（2）： 246-252 联系邮箱：陈丽梅，chenlimeikm@126.com

北方澙湖大叶藻植株枚订移植法的效果评估与适宜性分析

刘燕山，郭栋，张沛东，等

摘要：2009年利用植株枚订移植法在我国北方典型澙湖——山东荣成天鹅湖逐月进行大叶藻（Zostera marina）植株移植，并于当年逐月对移植植株的存活率、定居时间和生长进行监测，分析该方法在我国北方澙湖的有效性和适宜性.结果显示：（1）4-6月移植植株的存活率为76.5%-90.4%，其中4月移植植株的存活率最低，7-9月移植植株的存活率达到100%；（2）6-9月移植植株的定居时间均为1个月，5月移植植株的定居时间为2个月，而4月移植植株的定居时间长达4个月；（3）除个别监测月份外，移植植株的叶长和叶鞘长均显著小于天然植株，而茎节直径和根长均与天然植株无明显差异；（4）我国北方澙湖较适宜大叶藻植株移植的区域为海水透明度高、水深不超过1 m的潮下带，且底质为泥含量较高的泥砂底质海区，9月份是适宜的移植时间.

关键词：大叶藻；枚订法；存活率；定居时间；生长；海草

来源出版物：植物生态学报，2015，39（2）： 176-183

联系邮箱：张沛东，zhangpdsg@ouc.edu.cn